MathGroup Archive 2011

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: solution

  • To: mathgroup at smc.vnet.net
  • Subject: [mg118277] Re: solution
  • From: Bob Hanlon <hanlonr at cox.net>
  • Date: Wed, 20 Apr 2011 04:26:24 -0400 (EDT)

You need to provide starting values outside of the range {1, 100}

r1 = Union[Table[k /. FindRoot[
      BesselJ[0, k] + k BesselJ[1, k] == 0, {k, n}],
    {n, 1, 100}], SameTest -> (Abs[#1 - #2] < 10^-4 &)];

Length[r1]

33

r2 = Union[Table[k /. FindRoot[
      BesselJ[0, k] + k BesselJ[1, k] == 0, {k, n*Pi}],
    {n, 1, 100}], SameTest -> (Abs[#1 - #2] < 10^-4 &)];

Length[r2]

100

For more roots, use a larger max value for n.


Bob Hanlon

---- amelia Jackson <meli.jacson at gmail.com> wrote: 

=============
Dear MathGroup,

I have a problem. I want to find solution:
r := Table[
k /. FindRoot[BesselJ[0, k] + k BesselJ[1, k] == 0, {k, n}], {n, 1, 100}]

but I get about 30 roots. I need about 100 or more.
I think that "step" "n" tend to Pi

Please for help...

--

Bob Hanlon



  • Prev by Date: Re: solution
  • Next by Date: Demonstration Project Solution Desired
  • Previous by thread: Re: solution
  • Next by thread: Re: solution